Propeller



Patented Nov. 1, 1932 UNITED. STATES JOHN SQUIRES, OF DETROIT, MICHIGAN PROPELLER Application filed March 8,

This invention relates to propellers and particularly to air craft propellers.

Inthe manufacture of such propellers 1t is desirable to form'the blades separately, since they may individually be more conveniently handled and more readily fashioned to the desired form, than when they are 1ntegrated. In assembling the blades and hub it is also desirable to establish the same pitch relation of the blades to the plane of rotation, so that the reactions of blades may be b alanced, and undue stresses land vibration avoided.

It is one object of the invention to separately form the blades of a propeller and to so connect said blades to the propeller hub as to very strongly resist such centrifugal stresses as arise in use. y

Another object is to adapt propeller blades, upon their initial mounting upon the propeller hub to be rotatively adjusted on the hub, about the longitudinal axes of said propellers, and to provide complementary indicia upon the blade shanks and upon the hub to accurately indicate a desired uniformity of such rotative adjustment so as to definitely assure the same pitch relation between all of said blades and-the plane of rotation of the propeller.

A further object is to adapt the blades to be accurately adjusted to and from the axis of the hub to equalize their effective distances from said axis.

Still another object is to engage the propeller blade shanks in sockets upon the hub, to provide for the aforementioned adjustments of said Shanks in said sockets, and to adapt said sockets to be finally contractively clamped upon said Shanks.

These and various other objects the invention attains by the construction hereinafter described andillustrated in the accompanying drawing, wherein;

Fig. 1 is a partially broken side view of the central portion of a propeller embodying the invention, sectionallv showing the 'connection of one ofthe blade shanks to the hub.

Fig. 2 is a rear view of said portion, appearing asindicated at 2-2 in Figure 1.

1929. serial 110.8455304.

- Fig. 3 is a cross sectional view taken upon the line 3-3 of Figure 1.

iFig. 4 is a cross section on line 4 4 of Figure 1.

Fig. 5 is a fragmentary radial section through one wall of one of the blade receiving sockets, showing a blade shank engaging said wall, modified somewhat from the show-- ing of Figure 1.-

In these views, the reference character 1 designates the shaft-engaging sleeve of a propeller hub, said sleeve being formed in its opening with suitable key ways 2. A pair of sockets are carried by said sleeve in diametrically opposed relation, each comprising halves 3 and 4 meeting in a plane preferably transverse to the sleeve 1. The halves 3 are formed as integral project-ions upon said sleeve and the halves 4 are securedto said projections by two` rows of bolts 5. A slight clearance, indicated at 6 is left between the halvesA at one side of each socketso that a clamping effect may be exercised by the bolts 5 extending across such clearance (see Fig. 3).

The shan'ks 7 of the propeller blades are tubular, and so engaged with the hub sockets as to provide for an accurate positioning of said blades as regards the spacing of their Shanks from the hub axis and as regards the angular positions of said Shanks in the sockets.

To accurately regulate the spacing of the Shanks 7 from the hub axis, an exteriorly screw-threaded sectional collar 8, preferably comprising complementary halves, is rotative upon each shank and is adapted, after suitable adjustment of the shank to be clamped upon the latter within the correspending rsocket 3, 4. To accommodate said collars, the Shanks 7 are annularly channeled, as indicated. at 9, the end walls of said channels being curved gradually outward and the collar extremities being correspondingly interiorly curved. The screw threads of each 9' collar engage interior screw threads of the corresponding socket-3, 4, as appears at 10 `(Figure 1), so that a rotation of the collar, `(inadvance of fully tightening the bolts 5) will advance the shank toward or withdraw it from the hub axis. As a provision for turning them, the collars 8 are outwardly flangedadjacent to the outer ends of the sockets 3, 4, as indicated at 11 and radial pockets 12 are formed in said fianges for engagement by-a Spanner wrench or the like.

Centrifugal stresses act-ing upon the blades, in the use of the propeller, aretransmitted to the hub through the collars 8 and itis desirable that a considerable area of each collar receive such stresses rather than their inner ends only. Thus, it is preferred to slightly flare the collars 8 from their outer to their inner ends and to correspondingly taper the grooved portions of the blades, gripped by said collars, as Figure 1 clearly shows.

'Describing now the provision made for adjusting each propeller blade rota-tively in its socket, 13 designates a gauge piece or bar .extending upon and around the inner end of the member 4 of'each socket, through a suitable arc as for example one hundred and twenty degrees. Preferably the portion of each member 4 seating said bar is raised or embossed slightly as indicated at 14. Said gauge pieces when once located relative to the corresponding sockets 4, are held in the. describe dpositions by cap screws 15, a pair of which pass through the longitudinal slots 16 in the end portions of' each gauge piece, the latter being thus afforded a limited arcuate travel with respect to said screws when the latter are loosened. Projecting inwardly from said gauge piece, midway of its length, is a key 17 which fits snugly into an opening 18 in the shank 7 thus adapting said gauge piece to accurately indicate the rotative position of the blade. The opening 19 of the member 4 through which said key projects is slotted through a sufficient arc to afford the shank 7 (and gauge piece 13) such rotative play as mav be required. .U pon a l'ateral face of said gauge piece, a scale 2O is marked and a coacting Vernier scale is marked upon the boss 14, as indicated at 21. The cap screws 15^ are headed to hold the gauge piece 13 in place when loosened without restraining it from adjustment, and it is preferred to engage the heads of said cap screws by the out-turned ends of a locking strip`22 to prevent turning of said screws.

. In the modified construction shown by Fig. 5, apropeller blade shank 23 is rotatively embraced by a collar 24, externally threaded to engage the socket 25, this construction dif-1 fering from that already described only in that the inner face of said collar and the engaged portion of the shank 23 are annularly stepped, as indicated at 26 instead `of having the gradual flare of the first described construction. This will transmit centrifugal stresses arising in the shank to the series of annular steps formed in the lcollar and will exercise a lesser expansive/'bursting effect on the collar than will be true of the first described construction. f

In use of said construction,the collar 8 will be dis osed in the channel 9, embracing the shank and the latter will then be en' gaged, in approximately its final position with the socket member 3. The socket'member 4 will then be applied and the bolts' 5 tightened up but not sufiiciently'to interfere with rotation of the shank 7 or collar 8. The collars 8 may now be turned to adjust the blades outwardly or inwardly, as may be necessaryto equaliae their effective distance from the propeller axis. In effecting this adjustment, any desired member-may be held in fixed relation to the propeller and near the tips of the blades to gauge'their relative outward extent.

' To assure uniformity of pitch of the blades with regard to the plane of rotation ofthe propeller, the blades are turned unt1l the same relation is established between the scales 20 and -21 of both blades. y

Finally, thev bolts v5 are fully tightened, clamping the collars 8 firmly in the sockets 3, 4 and firmly clamping the Shanks 7 in said collars. i

The constructionis one that provides forl an accurately balanced initial assembly of a propeller and also permits accurately correct positioning of any blade that may be required to replace one originally provided.

While it will be apparentthat'the illustrated embodiment. of my invention herein disclosed is Well calculated to adequately fulfill the objects and advantages rimarily stated, it is to be understood that the invention said collar, 'and meansfor radially contracting said socket about said collar and shank.

2. A `propeller blade comprising a hub member having a contractible radial socket internally screw threaded, a propeller blade having a shank rotatively fitted in said socket, a split collar rotative uponsaid shank contractible to 4clamp said shank and restrained from longitudinal shifting upon the shank, said collar being externally threaded to engage the threads -of said socket whereby to permit radial -adjustment of said blade, and

means for contracting said socket to rigidly clamp said collar and shank. 3. In a propeller, in combination, a hub member having-a radially extending split socket, a propeller blade having a shank receivable in said socket, said shank having a circumferentially extending recess therein, and a split collar rotatably encircling the recessed portion of said shank and maintained against axial movement rela-tive thereto, said collar being received within said socket and having threaded engagement therewith and means to contract the socket.

4. In a propeller, in combination, a. hub member having a radially disposed socket, a propeller blade4 having a shank rotatably received in said socket, the inner end of said shank bearing against the side walls of said socket and said .shank beingcircumferentially recessed outwardly thereof, a split col-v lar encircling said shank and -received in-said recess against axial displacement with respect thereto, said collar being externally formed for screw threaded engagement with the interior walls of said socket, and means for radially contracting said socket whereby to clamp said collar between said socket and said shank.

5. In a propeller, in combination, a hub .Inember having a radially disposed sockel', a

propeller blade having a shank rotatably re-' ceived in said socket, the inner end of said shank bearing against the side walls of said socket and said shank being circumferentially recessed outwardlythereof, a split collar encircling said shank and received against axial displacement in said recess, said collar being externally formed for screw threaded engagement' with the interior wall's'of said socket, and4 means for radially contracting 4 said socket whereby to clamp said collar between said socket and said shank, and to clamp said shank directly by said collar.

6. -A propeller comprisingl a hub member havinga radial contractible socket, a propeller-blade having a shank in said socket, a split collar rotatively engaging said shank within the socket and being secured against Aaxial l Vdisplacement, with respect'to the shank, said collar and socket having engaging-screw threads, andmeans for contracting the colla-r into clamping engagement with said shank,

the collar. opening being flared toward the hub. axis and the shank being .correspondingly tapered, whereby centrifugal stresses to whichthe shank is subjected are transmitted l Y to an extended area of the collar.l

7. A propeller comprising ahub member having a contractible radial socket, a pro# peller blade having a shank engaged in said socket and formed with an annular channel v within the socketpa segmentalcollar embracing said shank within said channel and being secured against axial displacement with ref.

spect to the shank and. contractible toclamp the shank againstrotation, `said collar` and socket having screw-threaded engagement L for adjusting the shank to 'and' from theaxis of the hub member', and means for contractively clamping the socket upon said collar collar andthe inner end of the socket and projecting through the socket wall and adapted for a limited rotation in the socket wall.

9. In apropeller, in combination, a hub member provided with a radially extending socket, said socket being diametrically split into two halves one of which is integral with said hub and the other of which is detachably secured to the integrally formed half, a blade y having 'a circumferentially recessed shank received in said socket, and a split collar retained in said recess-and threadably engaging the walls of said socket the collar and the shank being secured for relative rotation vWithout axial displacement and means for rigidly clamping the socket, collar and shank together.

10. In a propeller, in combination, a hub member provided with a radiallyl extending socket, said socket being diametrically split into two halves, one of which is integral with saidhub and the other of which is detachably 'secured to the integrally formed half, a blade having a circumferentially recessed shank received in said socket, anda split collar retained in said recess against axial displacement with respect to the shank and thread,- ably engaging the walls o said socket, said detachable half adapted to clamp saidoollar and shank against axial or radial movement relative to said integral half when secured thereto. l

11. In a propeller, in combination, a hub member provided with a radially extending socket, a propeller blade having a shank received in said socket, said 'shank being provided with a, plurality of radially extending et, the shank and the collar being relatively rotatable with respect toeach other without relative axial displacement, the interior walls of said collarI being formed with a plurality of surfaces complementary to said thrust surfaces' for engagement therewith and means for contracting the socket to clamp the collar. i

12. In apropeller, in combination, a hub member provided vwith a radially extending socket element, a propeller blade having a shank element rotatably received in said sockf et element, a split collar interposed between -said elements and operatively engagin both, said collar being axially adJustable with re- Y 5 spect to the socket to vary the radial position I of said shank element in said socket and be- A ing rotatable without axial displacement relative to the shank to vary the rotatable relation between said elements, and additional y means for contracting said socket element about the "rstmentioned means and said shank element. Y

13. `A propeller blade having a shank, said shank having a smooth walled annular channel peripherally formed therein', the bottom of said channel tapering from one end thereof to the other end thereof and having abruptly curved end walls forming abutment surfaces.. Y 14. In a propeller, in combination, a hub having a socket,a propeller blade having a shank rotatably received in said socket, means v for contracting said socket about said shank to lock it in rotatably adjustedposition, said shank having an axially'parallel slot inthe periphery thereof, said socket Ahaving a slot therein transverse to said slot in said shank, an' indicating member overlying the margins of said slot in'said socket, a pin on said memberprojecting through said slot in said socket and slidably received, in said slot in said shank, and means'for securingsaid member against movement to said socket.

15. In a propeller, in combination, a hub having a socket, a propeller blade having a shank rotatably receivedin said socket, means for contracting said socket aboutsaid shank to lock it in rotatably adjusted position, said shank having an axially parallel slot in the 40 periphery thereof, said socket having a circumferential slot therein, a circumferentially elongated indicating member overlyin the margins of said slot in said socket,` a p1n on said member projecting through said slot in said socket and slidably engaging said slot in` said shank, said member having a. circumferentially extending slot therein, and clamp- 4ing means extending through saidl slot in y said ymember and engaging said 'socket for locking said member in adjustedposition.

JOHN sommes. .l 

